Hepatitis B

Caused by infection with the hepatitis B virus (HBV), which is most commonly passed to a partner during sexual intercourse, especially during anal sex, as well as through sharing of drug needles. Usually enters the body through blood transfusions contaminated with the virus or by the use of contaminated needles or instruments. Infection may be very severe and result in prolonged illness, cirrhosis or death.

Hepatitis B virus

Hepatitis

• Hepatitis means inflammation of the liver.
• When the liver is inflamed or damaged, its function can be affected.
• Heavy alcohol use, toxins, some medications, and certain medical conditions can all cause hepatitis.
• Hepatitis can also be caused by a virus.
• In the United States, the most common hepatitis viruses are hepatitis A virus, hepatitis B virus, and hepatitis C virus.
• Hepatitis A, Hepatitis B, and Hepatitis C are liver infections caused by three different viruses.
• Hepatitis B and hepatitis C can also begin as short-term infections but in some people, the virus remains in the body and causes chronic, or lifelong, infection.

Hepatitis B spread

Hepatitis B

Hepatitis B is a liver infection caused by the hepatitis B virus. Some people with hepatitis B are sick for only a few weeks (known as “acute” infection), but for others, the disease progresses to a serious, lifelong illness known as chronic hepatitis B.

Types

There are two types of hepatitis B, Acute and chronic hepatitis B

Acute hepatitis B

• Acute hepatitis B is a short-term illness that occurs within the first 6 months after someone is exposed to the hepatitis B virus.
• Some people with acute hepatitis B have no symptoms at all or only mild illness. For others, acute hepatitis B causes a more severe illness that requires hospitalization.

Chronic hepatitis B

• Some people, especially those who get infected in adulthood, are able to clear the virus from their bodies without treatment.
• For other people, acute hepatitis B leads to life-long infection known as chronic hepatitis B.
• Over time, chronic hepatitis B can cause serious health problems, including liver damage, cirrhosis, liver cancer, and even death.

Distribution of Hepatitis B

Risk factors

• Age plays a role in whether hepatitis B will become chronic.
• The younger a person is when infected with the hepatitis B virus, the greater the chance of developing chronic infection.
• About 9 in 10 infants who become infected go on to develop life-long, chronic infection.
• About one in three children who get infected before age 6 will develop chronic hepatitis B.
• By contrast, almost all older children (those aged ≥6) and adults infected with the hepatitis B virus recover completely and do not develop chronic infection.

Incidence - acute hepatitis

USA: In 2018, a total of 3,322 cases of acute (short-term) hepatitis B were reported to CDC. World: An estimated 257 million people are living with hepatitis B worldwide.

Chronic hepatitis B incidence

In 2016, an estimated 862,000 people were living with HBV infection

Transmission, Symptoms, and Treatment

HBV is transmitted through activities that involve percutaneous or mucosal contact with infectious blood or body fluids such as:

• sex with an infected partner;
• injection-drug use that involves sharing needles, syringes, or drug-preparation equipment;
• birth to an infected mother;
• contact with blood from or open sores on an infected person;
• exposures to needle sticks or sharp instruments; and
• sharing certain items with an infected person that can break the skin or mucous membranes (e.g., razors, toothbrushes, and glucose monitoring equipment), potentially resulting in exposure to blood.
• How long does HBV survive outside the body?
• HBV can survive outside the body and remains infectious for at least 7 days.

Hepatitis B virus

Cleaning contaminated surfaces

Any blood spills (including dried blood, which can still be infectious) should be disinfected using a 1:10 dilution of one part household bleach to 10 parts of water. Gloves should be worn when cleaning up any blood spills.

Risk groups

The following populations are at increased risk for becoming infected with HBV:

• Infants born to infected mothers
• Sex partners of infected people
• Men who have sex with men
• People who inject drugs
• Household contacts or sexual partners of known people with chronic HBV infection
• Health-care and public-safety workers at risk for occupational exposure to blood or blood-contaminated body fluids
• Hemodialysis patients

Engerix B (Hepatitis B) vaccine

Screening for HBV

• People born in countries with an HBV prevalence of ≥2%
• People born in the United States not vaccinated as infants whose parents were born in regions with high rates of HBV infection (HBsAg prevalence of ≥8%)
• Men who have sex with men
• People who inject drugs
• People with HIV
• Household and sexual contacts of HBV-infected people
• People requiring immunosuppressive therapy
• People with end-stage renal disease (including hemodialysis patients)
• Blood and tissue donors
• People with elevated alanine aminotransferase levels (>19 IU/L for women and >30 IU/L for men)
• Pregnant women (hepatitis B surface antigen [HBsAg] only is recommended)
• Infants born to HBV-infected mothers (HBsAg and antibody to hepatitis B surface antigen [anti-HBs] only are recommended)

International travellers

• The risk for HBV infection in international travelers is generally low, except for certain travelers to regions where the prevalence of chronic HBV infection is high or intermediate (i.e., HBsAg prevalence of ≥2%).
• Hepatitis B vaccination should be administered to unvaccinated people traveling to those countries.

Signs and symptoms

Not all people with acute HBV infection have symptoms. The presence of signs and symptoms varies by age. Most children <5 years of age and newly infected immunosuppressed adults are generally asymptomatic, whereas 30%–50% of people age ≥5 years have signs and symptoms including:

• fever,
• fatigue,
• loss of appetite,
• nausea,
• vomiting,
• abdominal pain,
• dark urine,
• clay-colored stool,
• joint pain, and
• jaundice.

Most people with chronic HBV infection are asymptomatic and have no evidence of liver disease or injury.

HBV replication

Incubation period

If symptoms occur, they begin an average of 90 days (range: 60–150 days) after exposure to HBV.

Acute hepatitis symptoms

Symptoms typically last for several weeks but can persist for up to 6 months. Approximately 25% of people who become chronically infected during childhood and 15% of those who become chronically infected after childhood die prematurely from cirrhosis or liver cancer, and most remain asymptomatic until onset of cirrhosis or end-stage liver disease.

Risk of chronic Hepatitis B

The risk for chronic infection varies according to the age at infection and is greatest among young children. Approximately 90% of infants and 25%–50% of children aged 1–5 years will remain chronically infected with HBV. By contrast, approximately 95% of adults recover completely from HBV infection and do not become chronically infected.

Lab tests

Three different serologic tests are needed (hepatitis B surface antigen [HBsAg], hepatitis B surface antibody [anti-HBs], and total hepatitis B core antibody [anti-HBc]) to determine whether a patient has acute or chronic HBV infection and is in need of post-test counseling and linkage to care.

Infectivity

• HBsAg will be detected in an infected person’s blood an average of 4 weeks (range: 1–9 weeks) after exposure to the virus.
• About half of patients will no longer be infectious by 7 weeks after onset of symptoms, and all patients who do not remain chronically infected will be HBsAg-negative by 15 weeks after onset of symptoms.

Treatment

People with acute infection are provided supportive treatment depending on their symptoms. For people with chronic infection, several antiviral medications are available; these patients require linkage to care with regular monitoring to prevent liver damage and/or hepatocellular carcinoma.

Reactivation

• HBV reactivation is the abrupt reappearance or rise in HBV DNA in a patient with previously inactive chronic or resolved hepatitis B.
• It is often accompanied by a flare in disease activity with elevation of liver enzymes with or without symptoms. HBV reactivation can be severe, resulting in death.
• Patients who test positive for both anti-HBc and HBsAg are at substantially higher risk of reactivation than are those who are positive for both anti-HBc and anti-HBs.

HBsAg

Others at risk include people:

• undergoing cancer chemotherapy;
• taking immunosuppressive therapy, including
• Rituximab and other drugs that target B lymphocytes (black box warning),
• high-dose steroids, and
• anti-TNF agent;
• with HIV infection who have discontinued therapy with antiretroviral drugs that also have activity against HBV;
• undergoing solid organ or bone marrow transplantation; and
• being treated for HCV coinfection.

HBV/hepatitis D virus (HDV) superinfection

Superinfection occurs when people with chronic, active HBV infection are subsequently infected with HDV. Superinfection exacerbates the symptoms of the chronic HBV infection and can lead to acute liver failure.

Hepatitis B Vaccination

The Advisory Committee on Immunization Practices (ACIP) recommends that the following people receive hepatitis B vaccination:

• All infants
• Unvaccinated children aged <19 years
• People at risk for infection by sexual exposure
• Sex partners of people testing positive for hepatitis B surface antigen (HBsAg)
• Sexually active people who are not in a long-term, mutually monogamous relationship (e.g., people with more than one sex partner during the previous 6 months)
• People seeking evaluation or treatment for a sexually transmitted infection
• Men who have sex with men
• People at risk for infection by percutaneous or mucosal exposure to blood
• People who currently inject or have recently injected drugs
• Household contacts of people who are HBsAg-positive
• Residents and staff of facilities for developmentally disabled people
• Health care and public safety personnel with reasonably anticipated risk for exposure to blood or blood-contaminated body fluids
• Hemodialysis patients and predialysis, peritoneal dialysis, and home dialysis patients
• People with diabetes aged 19–59 years; people with diabetes aged ≥60 years at the discretion of the treating clinician
• International travelers to countries with high or intermediate levels of endemic hepatitis B virus (HBV) infection (HBsAg prevalence of ≥2%)
• People with hepatitis C virus infection
• People with chronic liver disease (including, but not limited to, people with cirrhosis, fatty liver disease, alcoholic liver disease, autoimmune hepatitis, and an alanine aminotransferase ALT or aspartate aminotransferase AST level greater than twice the upper limit of normal)
• People with HIV infection
• People who are incarcerated
• All other people seeking protection from HBV infection

Hepatitis B

Single-antigen hepatitis B vaccines available in the US

• ENGERIX-B®
• RECOMBIVAX HB®
• HEPLISAV-B™

Combination vaccines

PEDIARIX®: Combined hepatitis B, diphtheria, tetanus, acellular pertussis (DTaP), and inactivated poliovirus (IPV) vaccine. Cannot be administered before age 6 weeks or after age 7 years. TWINRIX®: Combined Hepatitis A and hepatitis B vaccine. Recommended for people aged ≥18 years who are at increased risk for both HAV and HBV infections.

Hepatitis B vaccination schedule

• The vaccination schedule most often used for children and adults is three intramuscular injections, the second and third doses administered at 1 and 6 months, respectively, after the first dose.
• Alternate schedules have been approved for certain vaccines and/or populations. A new formulation, Heplisav-B (HepB-CpG, manufactured by Dynavax), is approved for two doses, 1 month apart.

Pregnant women and Hepatitis B vaccination

Pregnant women should receive HBsAg testing during each pregnancy, and those who are HBsAg-positive should have HBV DNA testing.

Vaccination during pregnancy and lactation

• The hepatitis B vaccine contains no live virus, so neither pregnancy nor lactation should be considered a contraindication to vaccination.
• Of the three available adult vaccines for hepatitis B, there is limited safety data for HEPLISAV-B, and as such, providers should continue to vaccinate pregnant women needing hepatitis B vaccina­tion with a vaccine from a different manufacturer.

Pregnant women that should be vaccinated with Hepatitis B:

• have had more than one sex partner during the previous 6 months,
• are being evaluated or treated for a sexually transmitted infection,
• have had recent or current injection-drug use, or
• have had a HBsAg-positive sex partner.

Post-exposure prophylaxis

• After a person has been exposed to HBV, appropriate prophylaxis, given as soon as possible but preferably within 24 hours, can effectively prevent infection.
• The mainstay of postexposure immunoprophylaxis is hepatitis B vaccine, but, in certain circumstances, the addition of HBIG provides increased protection.

Hepatitis B Resources
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